Eta1 Coronae Australis

Eta¹ Coronae Australis, Latinized from η¹ CrA, is a suspected astrometric binary^[10] star system in the constellation of Corona Australis. It is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of 5.456.^[2] Parallax measurements put it at a distance of 317 light-years away from the Sun.

For other stars with this Bayer designation, see η Coronae Australis.

η¹ Coronae Australis

Observation data Epoch J2000      Equinox J2000
Constellation	Corona Australis
Right ascension	18h 48m 50.49216s[1]
Declination	−43° 40′ 48.1977″[1]
Apparent magnitude (V)	5.456[2]
Characteristics
Spectral type	A3V[3]
B−V color index	+0.13[4]
Astrometry
Radial velocity (Rv)	−4.0±4.2[5] km/s
Proper motion (μ)	RA: 22.312[1] mas/yr Dec.: −14.139[1] mas/yr
Parallax (π)	10.2735±0.1889 mas[1]
Distance	317 ± 6 ly (97 ± 2 pc)
Absolute magnitude (MV)	0.84[6]
Details
Mass	2.05±0.29[7] M☉
Radius	3.43±0.12[7] R☉
Luminosity	51[7] L☉
Surface gravity (log g)	3.68±0.07[7] cgs
Temperature	8308±133[7] K
Metallicity [Fe/H]	−0.01[8] dex
Rotational velocity (v sin i)	122.3[9] km/s
Age	491[8] Myr
Other designations
Eta1 CrA, CD−43°12841, FK5 1490, HD 173715, HIP 92308, HR 7062, SAO 229299
Database references
SIMBAD	data

The visible component is an A-type main-sequence star with a stellar classification of A3V,^[3] which indicates it is generating energy through core hydrogen fusion. It has broad spectrum absorption lines associated with its rotation period, having a projected rotational velocity of 122.3 km/s.^[9] The star is radiating 51 times the luminosity of the Sun from its photosphere at an effective temperature of 8,308 K.^[7]